<p>Brenhin Keller and Kalin McDannell explore the origins of a worldwide gap in the geologic record spanning hundreds of millions to billions of years.</p>

Rising temperatures and European bird traits

Welcome to Science Sessions, the PNAS podcast program. Listen to brief conversations with cutting-edge researchers, Academy members, and policymakers as they discuss topics relevant to today's scientific community. Learn the behind-the-scenes story of work published in PNAS, plus a broad range of scientific news about discoveries that affect the world around us.